Why fly when you can walk? That's what the winged azhdarchid dinosaur apparently figured while on the hunt back in the day—65 million to 230 million years ago. Researchers at the University of Portsmouth in England report in PLoS ONE that the dinos were more likely to stalk prey on foot than by flying over and swooping in for the kill. Paleontologists generally believe that pterosaurs (the larger category of dinosaur to which the azhdarchid belongs) lived as gull- or pelican-like predators that flew over lakes and oceans, plucking fish from the water. But a study of azhdarchid anatomy, footprints and the distribution of their fossils indicates one size does not fit all in the case of flying reptiles. In fact, azhdarchids—which could grow as tall as giraffes, with wingspans of up to 33 feet (10 meters)—were probably better at walking than any other pterosaurs, because they had long limbs and skulls well suited for picking up small animals and other food from the ground. Azhdarchids' closest relatives today: large ground-feeding birds such as ground-hornbills and storks.

Coming to an airport near you?: Spray-on security

Researchers at the University of California, San Diego, have designed a new spray-on explosive detector sensitive enough to detect even miniscule amounts of nitrogen-containing explosives, according to a report this week in Royal Society of Chemistry's Journal of Materials Chemistry. The spray is actually a polymer that can detect explosives at much lower levels than existing systems because it distinguishes particles instead of explosive vapors. The polymer is able to show the difference between trinitroglycerin and nitroaromatic explosives, such as TNT. Initially, polymer-treated spots of both compounds appear blue under UV light, but after further exposure the trinitroglycerin blotch fluoresces green-yellow, whereas the TNT smear remains blue. The technology is now being commercially produced by RedXDefense, a security company based in Rockville, Md.

Does lead exposure lead to crime?

A new study shows that exposure to lead during infancy or childhood kills brain cells and boosts the chances of that child committing a crime later in life. Researchers, who tracked 250 lead-exposed children for three decades from their birth in 1979, found that levels of lead in the blood correlated with the risk of committing crimes. Study author Kim Dietrich, an environmental health scientist at the University of Cincinnati College of Medicine, reports in PLoS Medicine, that the odds of committing a crime as an adult jumped by 50 percent for every additional 10 millionths of an ounce (five micrograms) of lead per 3.3 fluid ounces (one deciliter) of blood at age six. Related research by Kim Cecil of Cincinnati Children's Hospital Medical Center published with this study in PLoS Medicine found that 157 of the subjects with the highest lead levels had the smallest brain sizes compared with normal adults, providing a possible mechanism for lead's effect on behavior.

Bug off: the next generation of insect repellants

Consumers may soon have other options when it comes to repelling pesky (and sometimes disease carrying) mosquitoes than potentially toxic DEET, the most common chemical repellant now used. Scientists funded by the U.S. Department of Defense have found seven new chemicals that repel mosquitoes up to three times longer than DEET, which, at full strength, can keep them away for more than 17 days. One potential candidate sprayed on cloth kept the skeeters away for a full 73 days. Full human safety tests are set to begin this summer on the potential anti-bug sprays that hail from a family of chemicals known as N-acylpiperidines, which are similar to piperine, the ingredient that gives black pepper its kick.

Scientists show how the brain "reads" nouns

A new study in Science says the human brain links persons, places and things (think: nouns) with their associated actions. That is, says study co-author Marcel Just, a Carnegie Mellon University psychologist, "an apple is what you do with it," and, so, when you see the word "apple," the brain processes it in regions that control what one ordinarily does with it: taste, smell or chew. Researchers uncovered this little nugget by scanning the brains of nine subjects as they thought about 60 nouns ranging from different parts of the body to fruits and vegetables. Those nouns had been categorized according the verbs most associated with them in the English language, be it eat, run, pull or whatever. "Door," for instance, would be associated with push, pull or open. The team fed the semantic links, along with the associated fMRI data, into a computer algorithm and was able to correctly predict 77 percent of the time how a person's brain scan would look when presented with certain new nouns.

Using baking soda to spot cancer earlier

It's supposed to be good for scrubbing your teeth and keeping your fridge sweet smelling. But now researchers from the University of Cambridge report in Nature that they used sodium bicarbonate (aka baking soda) to locate malignant tumors in mice. The finding paves the way for a new, noninvasive way of detecting tumors earlier, potentially sparing thousands of lives. The way it works: bicarbonate, an alkaline, rushes to areas in the body that are unnaturally acidic—including cancer cells—to try to balance them. Cancer cells release carbon dioxide when exposed to bicarbonate, which reduces the acidity. Knowing this, the researchers injected diseased mice with baking soda and were able to pinpoint tumors by their CO2 release, which was captured by an MRI machine 20,000 times more powerful than those commonly used. Study co-author and Cambridge biochemist Kevin Brindle told the BBC that the new technique also holds promise for showing how well tumors are responding to treatment. Human clinical trials are set to begin next year.

Dead Planet? Mars water may have been to salty for life

Microbial life on Mars may have died off as quickly as it evolved—a victim of over-seasoning, perhaps. NASA's Opportunity rover identified minerals on the Red Planet's Meridiani Planum that were most likely deposited by liquid water, long since evaporated. Now researchers have used geochemical models to calculate how salty that water would have been. They report in Science that those ancient ponds were far saltier than the vast majority of Earthly organisms could have tolerated, suggesting that life on Mars might never have had a chance.

Anonymous donor bails out Fermilab

Work furloughs instituted at the nation's sole surviving particle physics laboratory—Fermi National Accelerator Laboratory in Batavia, Ill., home to the massive Tevatron particle accelerator—will no longer be necessary, the lab's director told employees last week. An anonymous donation of $5 million to the University of Chicago should counteract the unexpected 2008 budget cuts that forced all employees to take off one week per month, although the lab says it will still have to lay off about 140 employees. It's not the first bailout of a U.S. particle physics lab; theoretical physicist and hedge-fund billionaire James Simons donated $13 million to Brookhaven National Laboratory in Upton, N.Y., in 2006 to keep the Relativistic Heavy Ion Collider running.

Frog legs with… claws?

Scientists have discovered that some African frogs have claws that burst through the skin of their toes much like those of Wolverine in X-Men. These frogs are the only vertebrates known to brandish claws in such a self-wounding manner. What's also surprising is that these claws are made of bone, rather than the hard protein called keratin that normally comprises fingernails, claws and hooves. Lead study author David Blackburn, a biologist from Harvard University, reports in Biology Letters that he had noticed that the flailing, kicking frogs left scratches on their antagonists' arms. He and other researchers then combed through museum frog specimens and discovered the bone-claws. Other scientists had mentioned their existence over the past century, but this is the first time it was confirmed. It appears, though, that Cameroon tribesmen were long aware of these amphibians' fierce secret weapon; they typically use long, nail-studded poles or machetes to lay blows to the frogs' heads when hunting to avoid getting slashed.